No Doubt In ConcertUNIVERSAL CITY, CA - NOVEMBER 30: No Doubt's Gwen Stefani and Tony Kanal perform at Gibson Amphitheatre on November 30, 2012 in Universal City, California. (Photo by Christopher Polk/Getty Images for Rebel Waltz)

Gwen StefaniNEW YORK - FEBRUARY 23: Gwen Stefani of No Doubt performs at the 45th Annual Grammy Awards at Madison Square Garden on February 23, 2003 in New York City. (Photo by Frank Micelotta/Getty Images)

Gwen Stefani In this handout image made available on March 1, 2007 by MTV, Gwen Stefani poses for a portrait shoot. Gwen Stefani was announced as one of the nominees for the MTV Australia Video Music Awards 2007, which take place in Sydney on April 29 at the Acer Arena. (Handout Photo by MTV/Getty Images) *** Local Caption *** Gwen Stefani

Gwen StefaniCANNES, FRANCE - MAY 16: (L-R) Rob Lowe, Gwen Stefani and Gavin Rossdale attend the cocktail reception for "Snow Flower and the Secret Fan" presented by IDG and Sponsored by Damiani, Dior and Penninsula Hotel at the Carlton Hotel on during the 64th Annual Cannes Film Festival at Palais des Festivals on May 16, 2011 in Cannes, France. (Photo by Michael Buckner/Getty Images)

Gwen StefaniGwen Stefani of the band No Doubt arrives for the 2001 Billboard Music Awards held at the MGM Grand Hotel and Casino in Las Vegas Nevada, December 4, 2001. (Photo by Frank Micelotta/Getty Images)

Gwen StefaniLAS VEGAS, NV - SEPTEMBER 21: Singer Gwen Stefani of No Doubt performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Photo by Christopher Polk/Getty Images for Clear Channel)

Gwen StefaniHOLLYWOOD - OCTOBER 21: Singer Gwen Stefani arrives at Gwen Stefani's celebration of the Harajuku Lovers Tour 2005 held at the Hollywood Museum in the Historic Max Factor Building on October 21, 2005 in Hollywood, California. The Harajuku Lovers Tour 2005 is a presentation and launch of apparel and accessories from Harajuku Lovers brand. (Photo by Vince Bucci/Getty Images)

Gwen Stefani In this handout image made available on March 1, 2007 by MTV, Gwen Stefani poses for a portrait shoot. Gwen Stefani was announced as one of the nominees for the MTV Australia Video Music Awards 2007, which take place in Sydney on April 29 at the Acer Arena. (Handout Photo by MTV/Getty Images)

Gwen StefaniUNIVERSAL CITY, CA - JULY 22: Singer Gwen Stefani of the rock band No Doubt performs at the Gibson Amphitheatre on July 22, 2009 in Universal City, California. (Photo by Kevin Winter/Getty Images for Rebel Waltz)

Gwen StefaniNEW YORK - OCTOBER 23: Gwen Stefani attends a celebration for the publication of "Stylist: The Interpreters of Fashion" hosted by Style.com on October 23, 2007 in New York City. (Photo by Andrew H. Walker/Getty Images)

No Doubt In ConcertUNIVERSAL CITY, CA - NOVEMBER 30: Gwen Stefani and members of No Doubt perform at Gibson Amphitheatre on November 30, 2012 in Universal City, California. (Photo by Christopher Polk/Getty Images for Rebel Waltz)

Gwen StefaniSinger Gwen Stefani appears with her wax figure after it was unveiled at Madame Tussauds Las Vegas at the Venetian Resort Hotel Casino September 22, 2010 in Las Vegas, Nevada.

No Doubt In ConcertNEW YORK, NY - SEPTEMBER 05: (L-R) Tom Dumont, Adrian Young, Gwen Stefani and Tony Kanal of No Doubt perform onstage during the 2012 NFL Kick-Off Concert in Rockefeller Center on September 5, 2012 in New York City. (Photo by Bryan Bedder/Getty Images)

Gwen StefaniLAS VEGAS, NV - SEPTEMBER 21: Singer Gwen Stefani of No Doubt performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Photo by Isaac Brekken/Getty Images for Clear Channel)

Gwen StefaniNEW YORK, NY - MAY 06: [EDITOR'S NOTE: image has been digitally processed and converted to black and white] Gwen Stefani attends the Costume Institute Gala for the "PUNK: Chaos to Couture" exhibition at the Metropolitan Museum of Art on May 6, 2013 in New York City. (Photo by Andrew H. Walker/Getty Images for People.com)

No Doubt In ConcertUNIVERSAL CITY, CA - NOVEMBER 30: No Doubt's Gwen Stefani performs at Gibson Amphitheatre on November 30, 2012 in Universal City, California. (Photo by Christopher Polk/Getty Images for Rebel Waltz)

No Doubt In ConcertUNIVERSAL CITY, CA - NOVEMBER 30: No Doubt's Gwen Stefani performs at Gibson Amphitheatre on November 30, 2012 in Universal City, California. (Photo by Christopher Polk/Getty Images for Rebel Waltz)

Gwen StefaniLOS ANGELES, CA - NOVEMBER 18: Singer Gwen Stefani of No Doubt attends the 40th American Music Awards held at Nokia Theatre L.A. Live on November 18, 2012 in Los Angeles, California. (Photo by Jason Merritt/Getty Images)